The present invention comprises a new and distinct cultivar of Thuja occidentalis known by the varietal name ‘Silvanus 1’. The new variety was discovered by the breeder as a naturally-occurring branch (sport) mutation of Thuja occidentalis ‘Smaragd’ in West Hungary. ‘Silvanus 1’ was first asexually reproduced by semi-hardwood cuttings in West Hungary. The new variety has been trial and field tested and has been found to retain its distinctive characteristics and remain true to type through successive propagations. Table 1 illustrates characteristics that distinguish ‘Silvanus 1’ from its parent plant, ‘Smaragd’.
                                         TABLE 1        Characteristic‘Silvanus 1’‘Smaragd’   Plant habitOvoidConicPlant speed of growthSlowMediumColor of upper leaf side inLight greenGreenSummerSide branch positionVerticalHorizontalScale leaf widthNarrowMediumScale leaf thicknessThin to mediumMedium